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/*

 * Copyright (C) 2005 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include <console/kconsole.h>

#include <console/console.h>

#include <console/chardev.h>

#include <print.h>

#include <panic.h>

#include <typedefs.h>

#include <arch/types.h>

#include <list.h>

#include <arch.h>

#include <func.h>

#include <macros.h>

#include <debug.h>

#define MAX_CMDLINE 256

/** Simple kernel console.

 *

 * The console is realized by kernel thread kconsole.

 * It doesn't understand any useful command on its own,

 * but makes it possible for other kernel subsystems to

 * register their own commands.

 */

/** Locking.

 *

 * There is a list of cmd_info_t structures. This list

 * is protected by cmd_lock spinlock. Note that specially

 * the link elements of cmd_info_t are protected by

 * this lock.

 *

 * Each cmd_info_t also has its own lock, which protects

 * all elements thereof except the link element.

 *

 * cmd_lock must be acquired before any cmd_info lock.

 * When locking two cmd info structures, structure with

 * lower address must be locked first.

 */

spinlock_t cmd_lock;    /**< Lock protecting command list. */

link_t cmd_head;    /**< Command list. */

static cmd_info_t *parse_cmdline(char *cmdline, size_t len);

static bool parse_argument(char *cmdline, size_t len, index_t *start, index_t *end);

/** Data and methods for 'help' command. */

static int cmd_help(cmd_arg_t *argv);

static cmd_info_t help_info;

/** Data and methods for 'description' command. */

static int cmd_desc(cmd_arg_t *argv);

static void desc_help(void);

static cmd_info_t desc_info;

static char desc_buf[MAX_CMDLINE+1];

static cmd_arg_t desc_argv = {

    .type = ARG_TYPE_STRING,

    .buffer = desc_buf,

    .len = sizeof(desc_buf)

};

/** Data and methods for 'halt' command. */

static int cmd_halt(cmd_arg_t *argv);

static cmd_info_t halt_info;

/** Initialize kconsole data structures. */

void kconsole_init(void)

{

    spinlock_initialize(&cmd_lock, "kconsole_cmd");

    list_initialize(&cmd_head);

    help_info.name = "help";

    help_info.description = "List supported commands.";

    help_info.func = cmd_help;

    help_info.help = NULL;

    help_info.argc = 0;

    help_info.argv = NULL;

    spinlock_initialize(&help_info.lock, "kconsole_help");

    link_initialize(&help_info.link);

    if (!cmd_register(&help_info))

        panic("could not register command %s\n", help_info.name);

    desc_info.name = "describe";

    desc_info.description = "Describe specified command.";

    desc_info.help = desc_help;

    desc_info.func = cmd_desc;

    desc_info.argc = 1;

    desc_info.argv = &desc_argv;

    spinlock_initialize(&desc_info.lock, "kconsole_desc");

    link_initialize(&desc_info.link);

    if (!cmd_register(&desc_info))

        panic("could not register command %s\n", desc_info.name);

    halt_info.name = "halt";

    halt_info.description = "Halt the kernel.";

    halt_info.func = cmd_halt;

    halt_info.help = NULL;

    halt_info.argc = 0;

    halt_info.argv = NULL;

    spinlock_initialize(&halt_info.lock, "kconsole_halt");

    link_initialize(&halt_info.link);

    if (!cmd_register(&halt_info))

        panic("could not register command %s\n", halt_info.name);

}

/** Register kconsole command.

 *

 * @param cmd Structure describing the command.

 *

 * @return 0 on failure, 1 on success.

 */

int cmd_register(cmd_info_t *cmd)

{

    ipl_t ipl;

    link_t *cur;

    ipl = interrupts_disable();

    spinlock_lock(&cmd_lock);

    /*

     * Make sure the command is not already listed.

     */

    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {

        cmd_info_t *hlp;

        hlp = list_get_instance(cur, cmd_info_t, link);

        if (hlp == cmd) {

            /* The command is already there. */

            spinlock_unlock(&cmd_lock);

            interrupts_restore(ipl);

            return 0;

        }

        /* Avoid deadlock. */

        if (hlp < cmd) {

            spinlock_lock(&hlp->lock);

            spinlock_lock(&cmd->lock);

        } else {

            spinlock_lock(&cmd->lock);

            spinlock_lock(&hlp->lock);

        }

        if ((strncmp(hlp->name, cmd->name, strlen(cmd->name)) == 0)) {

            /* The command is already there. */

            spinlock_unlock(&hlp->lock);

            spinlock_unlock(&cmd->lock);

            spinlock_unlock(&cmd_lock);

            interrupts_restore(ipl);

            return 0;

        }

        spinlock_unlock(&hlp->lock);

        spinlock_unlock(&cmd->lock);

    }

    /*

     * Now the command can be added.

     */

    list_append(&cmd->link, &cmd_head);

    spinlock_unlock(&cmd_lock);

    interrupts_restore(ipl);

    return 1;

}

/** Kernel console managing thread.

 *

 * @param arg Not used.

 */

void kconsole(void *arg)

{

    char cmdline[MAX_CMDLINE+1];

    cmd_info_t *cmd_info;

    count_t len;

    if (!stdin) {

        printf("%s: no stdin\n", __FUNCTION__);

        return;

    }

    while (true) {

        printf("%s> ", __FUNCTION__);

        if (!(len = gets(stdin, cmdline, sizeof(cmdline))))

            continue;

        cmdline[len] = '\0';

        cmd_info = parse_cmdline(cmdline, len);

        if (!cmd_info)

            continue;

        (void) cmd_info->func(cmd_info->argv);

    }

}

/** Parse command line.

 *

 * @param cmdline Command line as read from input device.

 * @param len Command line length.

 *

 * @return Structure describing the command.

 */

cmd_info_t *parse_cmdline(char *cmdline, size_t len)

{

    index_t start = 0, end = 0;

    cmd_info_t *cmd = NULL;

    link_t *cur;

    ipl_t ipl;

    int i;

    if (!parse_argument(cmdline, len, &start, &end)) {

        /* Command line did not contain alphanumeric word. */

        return NULL;

    }

    ipl = interrupts_disable();

    spinlock_lock(&cmd_lock);

    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {

        cmd_info_t *hlp;

        hlp = list_get_instance(cur, cmd_info_t, link);

        spinlock_lock(&hlp->lock);

        if (strncmp(hlp->name, &cmdline[start], (end - start) + 1) == 0) {

            cmd = hlp;

            break;

        }

        spinlock_unlock(&hlp->lock);

    }

    spinlock_unlock(&cmd_lock);

    if (!cmd) {

        /* Unknown command. */

        printf("Unknown command.\n");

        interrupts_restore(ipl);

        return NULL;

    }

    /* cmd == hlp is locked */

    /*

     * The command line must be further analyzed and

     * the parameters therefrom must be matched and

     * converted to those specified in the cmd info

     * structure.

     */

    for (i = 0; i < cmd->argc; i++) {

        char *buf;

        start = end + 1;

        if (!parse_argument(cmdline, len, &start, &end)) {

            printf("Too few arguments.\n");

            spinlock_unlock(&cmd->lock);

            interrupts_restore(ipl);

            return NULL;

        }

        switch (cmd->argv[i].type) {

            case ARG_TYPE_STRING:

                buf = cmd->argv[i].buffer;

                strncpy(buf, (const char *) &cmdline[start], min((end - start) + 1, cmd->argv[i].len - 1));

            buf[min((end - start) + 1, cmd->argv[i].len - 1)] = '\0';

            break;

            case ARG_TYPE_INT:

            case ARG_TYPE_INVALID:

            default:

            panic("invalid argument type\n");

            break;

        }

    }

    start = end + 1;

    if (parse_argument(cmdline, len, &start, &end)) {

        printf("Too many arguments.\n");

        spinlock_unlock(&cmd->lock);

        interrupts_restore(ipl);

        return NULL;

    }

    spinlock_unlock(&cmd->lock);

    interrupts_restore(ipl);

    return cmd;

}

/** Parse argument.

 *

 * Find start and end positions of command line argument.

 *

 * @param cmdline Command line as read from the input device.

 * @param len Number of characters in cmdline.

 * @param start On entry, 'start' contains pointer to the index

 *        of first unprocessed character of cmdline.

 *        On successful exit, it marks beginning of the next argument.

 * @param end Undefined on entry. On exit, 'end' points to the last character

 *        of the next argument.

 *

 * @return false on failure, true on success.

 */

bool parse_argument(char *cmdline, size_t len, index_t *start, index_t *end)

{

    int i;

    bool found_start = false;

    ASSERT(start != NULL);

    ASSERT(end != NULL);

    for (i = *start; i < len; i++) {

        if (!found_start) {

            if (is_white(cmdline[i]))

                (*start)++;

            else

                found_start = true;

        } else {

            if (is_white(cmdline[i]))

                break;

        }

    }

    *end = i - 1;

    return found_start;

}

/** List supported commands.

 *

 * @param argv Argument vector.

 *

 * @return 0 on failure, 1 on success.

 */

int cmd_help(cmd_arg_t *argv)

{

    link_t *cur;

    ipl_t ipl;

    ipl = interrupts_disable();

    spinlock_lock(&cmd_lock);

    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {

        cmd_info_t *hlp;

        hlp = list_get_instance(cur, cmd_info_t, link);

        spinlock_lock(&hlp->lock);

        printf("%s - %s\n", hlp->name, hlp->description);

        spinlock_unlock(&hlp->lock);

    }

    spinlock_unlock(&cmd_lock);

    interrupts_restore(ipl);

    return 1;

}

/** Describe specified command.

 *

 * @param argv Argument vector.

 *

 * @return 0 on failure, 1 on success.

 */

int cmd_desc(cmd_arg_t *argv)

{

    link_t *cur;

    ipl_t ipl;

    ipl = interrupts_disable();

    spinlock_lock(&cmd_lock);

    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {

        cmd_info_t *hlp;

        hlp = list_get_instance(cur, cmd_info_t, link);

        spinlock_lock(&hlp->lock);

        if (strncmp(hlp->name, (const char *) argv->buffer, strlen(hlp->name)) == 0) {

            printf("%s - %s\n", hlp->name, hlp->description);

            if (hlp->help)

                hlp->help();

            spinlock_unlock(&hlp->lock);

            break;

        }

        spinlock_unlock(&hlp->lock);

    }

    spinlock_unlock(&cmd_lock);

    interrupts_restore(ipl);

    return 1;

}

/** Print detailed description of 'describe' command. */

void desc_help(void)

{

    printf("Syntax: describe command_name\n");

}

/** Halt the kernel.

 *

 * @param argv Argument vector (ignored).

 *

 * @return 0 on failure, 1 on success (never returns).

 */

int cmd_halt(cmd_arg_t *argv)

{

    halt();

    return 1;

}